eMJA: In Other Journals, 17 August 2009

Having an endoscopy may soon be as simple as swallowing a specially designed capsule consisting of a tiny endoscope with a video camera at both ends. In an effort to assess the specificity and sensitivity of the method, capsule endoscopy has been compared with traditional optical colonoscopy in a multicentre, prospective trial. All 328 participants in the study had known or suspected colonic disease, and each underwent both capsule endoscopy and optical colonoscopy, which was considered the standard for comparison. The sensitivity of the capsule for detecting polyps that were 6 mm in size or greater was 64% and for advanced adenoma, 73%. The sensitivity of the method was higher in patients with better colon cleanliness after colonic preparation. The authors conclude that, although capsule endoscopy allows visualisation of the colonic mucosa without sedation or sufflation, its sensitivity is still low compared with optical colonoscopy.

The burden of liver cancer

Patients with chronic liver disease should be screened regularly for hepatocellular carcinoma, as the results of delayed diagnosis are devastating, according to New Zealand expert Edward Gane. In a discussion of the controversy surrounding screening for liver cancer, the author calls for an optimal screening interval of 6 months, using serum alpha fetoprotein measurement and abdominal ultrasound. Patients at greatest risk — those with cirrhosis and chronic hepatitis B infection — could then be diagnosed at an early stage, when treatment still has a chance of cure. An accompanying review by Warner and colleagues discusses the use of antiviral drugs for hepatitis B aimed at preventing the development of hepatocellular carcinoma, and outlines the emergence of drug resistance in the hepatitis B virus that has the potential to accelerate progression of liver disease to cancer.

Cancer Forum 2009; 33: July 2009 Online

Ovarian cancer and HRT

Enquiry into the relationship between postmenopausal hormone therapy and ovarian cancer continues, with a Danish study aimed at assessing the risks of different formulations of hormone therapies. In a nationwide, prospective cohort study spanning 10 years and including almost 1 million women aged 50–75 years, prescribing data and information from cancer and pathology registries were analysed. Results showed an increased risk of ovarian cancer even with short durations of hormone use (0–4 years) and no significant difference in risk with route of administration and dose, or between oestrogen alone and combined therapy. In practical terms, the absolute risk of 0.12 per 1000 years would have resulted in about 140 extra cases of ovarian cancer in Denmark over the mean follow-up of 8 years. This accounts for 5% of the total ovarian cancers detected in the study. The authors comment that although the figure seems low, ovarian cancer remains highly fatal, and that the risk should be considered when prescribing hormone therapy.

JAMA 2009; 302: 298-305

Mammography — the risk of overdiagnosis

Overdiagnosis, the detection of abnormalities that will not cause symptoms or death in a person’s lifetime, remains the bane of screening programs. According to the authors of a systematic review of breast cancer incidence, mammography screening may also be prone to the problems of overdiagnosis and the potentially damaging overtreatment that follows.1 Incidence data covering at least 7 years before and after mammography screening had been fully implemented were analysed — including the results of studies from the United Kingdom, Canada, Australia, Sweden and Norway. The results showed that, in populations offered organised breast cancer screening, overdiagnosis was 52% when carcinoma in situ was included and 35% for invasive breast cancer only. This translates as the overdiagnosis of one in three breast cancers. The observation remained stable when the researchers took into account an assumption of the increasing background incidence of breast cancer in these populations. An accompanying editorial states that “the question is no longer whether overdiagnosis occurs, but how often it occurs”.2 The author comments that women need to be informed of the trade-off between the number of deaths from breast cancer and those overdiagnosed and calls for more research, not only into women’s choices based on this information, but into refining estimates of overdiagnosis and minimising its occurrence.

1. BMJ 2009; 339: b2587

2. BMJ 2009; 339: b1425

Dr Tanya Grassi, MJA

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